Chapter 1 Overview of Wireless Standards, Organizations, and Fundamentals

Exam Essentials Know the three industry organizations –Understand the roles and responsibilities of the regulatory domain authorities, the IEE, and the Wi-Fi Alliance. Understand Core, Distribution and Access –Know where technology is deployed in fundamental network design Understand wavelength, frequency, amplitude, and phase –Know the definitions of each RF characteristics Understand the concepts of modulation –ASK, FSK, PSK are three carrier signal modulation techniques

History of WLAN Trace back to 19 th century scientists –Radio Frequency WWII –Tramsitting encrypted plans over RF Spread Spectrum Technology created 1970s-Aloha Net 1990s-Early commercial development Pg 2

Standards Organizations FCC IEEE Wi-Fi Alliance ISO Pg 3

FCC Regulates Communication in the US Regulate Licensed and Unlicensed –Wireless LAN mostly in unlicensed Regulates: –Frequency –Bandwidth –Maximum Power of the intentional Radiator –Maximum equivalent isotropically radiated power (EIRP) –Use (indoor and/or outdoor) Pg 3

FCC Regulates Communication in the US Regulate Licensed and Unlicensed –Wireless LAN mostly in unlicensed Regulates: –Frequency –Bandwidth –Maximum Power of the intentional Radiator –Maximum equivalent isotropically radiated power (EIRP) –Use (indoor and/or outdoor) Pg 3

Federal Communications Commission Manage RF for USA wireless can use both licensed and unlicensed frequencies Unlicensed means no cost to users –2.4 Ghz industrial, scientific and Medical (ISM) –5 Ghz Unlicensed National Inforamtion Infrastructure (UNII) band Pg 5

ITU-R Manages global spectrum of RF Pg 6

IEEE Defines the 802 series standards –802.3 Ethernet – Wireless Document the technical and equipment basics –Can be different interpretations Pg 7

Wi-Fi Alliance Starting with b manufacturers formed WECA –Promote technology –Support interoperability In 2000, WECA became WiFi Alliance Pg 8

Interoperability Certifications Addressed the issue of standards Help growth and progression Allow interoperability Pg 8

Wi-Fi Protected Access (WPA) Certification Overview Created due to weak security in initial standards Interim solution before i –Temporal Key Integrity Protocol (TKIP) –Passphrase –802.1X/EAP Two Modes –Personal Home Office –Enterprise Larger Deployment (Servers) Pg 8

Wi-Fi Protected Access 2 (WPA 2.0) Certification Overview Post i –WPA 2.0 Personal and Enterprise More advanced security –Personal mode security uses a passphrase Generates a 256 bit preshared key –Enterprise mode uses 802.1X/EAP Port based authentication designed for enterprises Strong security and external authentication Pg 8

Wi-Fi Protected Access 2 (WPA 2.0) Certification Overview WiFi Alliance Security Mechanism Authentication Mechanism Cipher Suite/Encryption Mechanism WPA-PersonalPassphraseTKIP/RC4 WPA_Enterprise802.1x/EAPTKIP/RC4 WPA2.0 PersonalPassphraseCCM/AES or TKIP/RC x/EAPCCM/AES or TKIP/RC4 Pg 8

Wi-Fi Multimedia (WMM) Certification Overview Proactive certification for 802.1e –Address QOS for wireless networks WMM Validates the features of e –Vendor neutral QOS approach –Ciritical for interoperability Pg 8

Wi-Fi Multimedia Power Save (WMM-PS) Certification Overview Designed for Mobile devices with battery issues –VoIP Phones –Notebooks –PDAs –Headsets –Mice –Keyboards Allow “dozing” to save battery May affect performance Pg 8

Wi-Fi Protected Setup (WPS) Certification Overview Designed for simple set up of wireless for SOHO networks Requires support for two types of authentication –Push Button Config (PBC) –PIN based config Enables automatic configuration of network names and WPA2 security Both methods need to be supported Near Field Communications also supported Pg 8

ISO Identifies standards for business, government and society Created the OSI model for computers networking –Not implemented, but often referenced Should understand the layers Pg 11

OSI Model –Layer 7- Application –Layer 6-Presentation –Layer 5- Session –Layer 4- Transport –Layer 3-Network –Layer 2-Data Link LLC MAC –Layer 1-Physical Please Do Not Throw Sausage Pizza Away All People Seem To Need Data Processing Pg 11

Core, Distribution, Access Core –No routing-High Speed Switching –Redundant Solutions Distribution –Router Traffic between LANS/VLANS –Wireless Bridges can operate here Access –Slower delivery to end user devices –To the desktop – Mostly implemented at access layer Access points Pg 12

Communications Fundamentals Most people have a basic idea about transfer of data This section gives more background on fundamental communications for wireless Pg 14

Carrier Signals Need to be able to transmit two states: –1 or 0 AC or DC alone wont do it, need to alternate or modulate The base signal that is modified is called the Carrier Signal The method of adjusting it is the modulation technique Pg 13

Amplitude and Wavelength Pg 14

Key wave terms Amplitude is a measure of the height of a wave. The higher the amplitude, the higher the power. Wavelength is the measure of the length between peaks. Frequency is how often the peaks come in a period of time, usually measured in Hertz (times per second). Phase is usually used to refer to the relationship between two waveforms of the same frequency. Phase is measured in degrees. Pg 15

Amplitude and Wavelength Pg 15

Phase Pg 15

Keying Methods Signal transmitted from the transceiver has to be manipulated to let receiver distinguish between 1 and 0 –This is the keying method –Also known as modulation techniques Amplitude Shift Keying Frequency Shift Keying Phase Shift Keying Pg 16

Current State Keying Uses the current (in time) value to show a 1 or 0 Whatever the current state is is the binary 0 –Other state is 1 Pg 16

State Transition Keying The change, or lack of change will signify a 0 or 1 0 is a change in state 1 is no change in state of signal Pg 16

Amplitude-Shift Keying Uses the height, or amplitude of the wave to signal change. Current state technique –A shift indicates a change from current signal Pg 17

Frequency-Shift Keying Uses the frequency, or number of cycles per second to indicate change. Current state technique –A shift indicates a change from current signal Used in legacy (older) technologies Pg 17

Phase-Shift Keying Varies the phase of a signal to represent data State Transition technique Pg 17

Phase-Shift Keying-Advanced Can encode multiple bits per symbol as well –Use four different phases Multiple Phase shift Keying Pg 17

Exam Essentials Know the three industry organizations –Understand the roles and responsibilities of the regulatory domain authorities, the IEE, and the Wi-Fi Alliance. Understand Core, Distribution and Access –Know where technology is deployed in fundamental network design Understand wavelength, frequency, amplitude, and phase –Know the definitions of each RF characteristics Understand the concepts of modulation –ASK, FSK, PSK are three carrier signal modulation techniques Pg 21